AR10 Mag Well Block04/11/2014ByRick KWorks perfect for lite duty work on the lower receiver. I use it with my Tipton Best Gun Vice and its as stable and well fitting as the ar15 style that Wheeler makes. A very handy tool to have on hand.
http://www.exploreproducts.com has the best prices and super quick shipping.

Center support slides into the magazine well and provides a steady base for cleaning or light gunsmithing on your AR-10